Quicksilver-furnace.



No. 643,839. Patented Feb. 20, |900. H. c. DAvEY. Y

QUICKSILVER FUBNACE. (Appli tion med my 1, 1899.)

' UNITED STATES PATENT EEICE.

HUGH C. DAVEY, OF CALISTOGA, CALIFORNIA.

DLUICKSILVERLFURNAC.

sP'EcIrIcATIVN forng part of Letters Patent No. 643,839, dated February 2o, 1900.

' Application tied May 1, 1899. sain No. 715,144.. (No man.)

To @ZZ whom it may concern,.-

Be it known that I, HUGH C. DAVEY, .a citi- 'zen of the United States, residing at Calistoga, county of Napa, State of California, have invented an Improvement in Quicksilver-Furnaces; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to improvements in furnaces of that class that are designed to extract metals, and especially Quicksilver, from the ores.

It consists in the parts and in the constructions and combinations of parts hereinafter described and claimed.

Figure l is a lateral section through the furnace through line a: of Fig. 2. Fig. 2 is a longitudinal section on the line y y through the center of one of the chambers.

In the roasting of quicksilver ores it has been customary to place the ore in the roasting-furnace, so that the moisture from the wet ore is expelled through the same exit with the fumes arising from the roasting of the ore, and the result has been a very considerable loss of quicksilver on account of the vapors of the quicksilver being carried off by the escaping water-vapor and the formation of mercury-soot or acid compounds,which make it difficult to properly condense and save the mercury. In some cases the ores have been dried upon exterior tables and have been placed in the furnace; but this does not avoid the difficulty, since the ore will reabsorb some moisture from the atmosphere before it goes into the roasting portion of the furnace.

I am not prepared to accurately state the reactions which take place; but it seems that without the presence of moisture the air being rarefied and highly heated causes the dust-salts, wood-ash, and sulfurous soots to deposit in what is called the dust-chamber of the condensing plant. The mercury still being in a volatile state passes farther on into the cooler condensers, where it is condensed into the metallic form, practically free from combinations with the substances above mentioned. y

In moist or humid air the sulf urous and other acid gases and soots have a stronger affinity, and thus form a sulfate of mercury and mercury-soots,which are thrown down in the dustl chamber,and thereby a proportion of the mercuryis lost at this point. In some ore' where niter is found in combination with the quicksilver ore and volatilized withy the mercury it is afterward condensed with the water and forms a nitric acid, which dissolves the mercury and carries it off in solution through the waste-water drains. In this case the nitric acid also eats and destroys the iron and brick condensers. In the same way dilute sulfuric acid is formed, which also destroys the condensers, and the solution mixed through the condensed mercury forms mercuric soot and acid compounds.

In my invention I have formed my furnace with an upper drying-chamber and a lower roastingchamber, with direct intercommunication, so that the ore after being thoroughly and perfectly dried at a comparatively-low temperature passes directly into the roasting portion of the furnace, where it is exposed to the higher temperature necessary to separate the metal from its combinations.

As shown in the drawings, A A are the walls of a furnace, the interior forming two chambers B and C, situated one above the other and connected by narrow channels D. In the drawing Fig. l I show these chambers in duplicate, there being one set of upper and lower chambers at each side of the vertical central line of the furnace. Each portion of the furnace is provided with the alternatelyinclined overlapping shelves E usual to this class of furnace, and the ore to be roasted is delivered into the uppermost chamber by means of a feed-chute F. The ore thus delivered passes down, sliding over the upper shelves outwardly, thence returninginwardly over the next pair, and thus moving alternately out and in until it reaches the bottom, and when the furnace has been lled the withdrawing of the spent ore through the passages H at the bottom of the furnace allows a new supply of ore to enter at the top. In order to apply the heat,iireplaces are built, as shown at I and J. The upper replace is intended to produce a low heat of a temperature sufficient to drive olf all moisture and thoroughly dry the ore, but not sufficient to roast, desulfurize, and vaporize the mercury, while the IOC efiaeee lower furnace has a stronger fire built in it, raising the temperature sufficiently to roast the ore after it reaches this furnace.

The inner walls K K at each end of the upper furnace are made with openings called pigeonholes, these openings being so placed with relation to the shelves that the products of combustion and the vapors arising from the heat will pass through the passages formed beneath the inclined shelves above the ore, and thence escape through the openings K in the opposite wall. I prefer to make the openin gs nearest the fireplace slnallest and those at the opposite end larger, so that the' gradual expansion of the heated products will produce a draft escaping into the passage L, and thence through a suitable escape-fine, the passages being made continuallylarger, so as to produce a strong draft.

In order to prevent the inner wall K which is contiguous to the fireplace .I from being heated to too great a temperature, I have introduced a supplemental wall K between this wall and the fireplace, this intermediate wall K having openings through it through which the heat passes, and an intermediate space between the two walls, which the heat must cross before passing the inner wall K. This construction prevents the undue heating of the inner wall, and a sufficient heat is passed through this part of the apparatus to thoroughly dry the ore and drive of all moisture. From this drying portion of the furnace the ore passes directly through passages D into the lower part of the furnace, where it is received upon similarly-inclined shelves, as before stated, and the end walls O of this portion of the apparatus are provided with pigeonholes or openings similar to those above described, through which the heat from the lower fireplace J passes over and through the body of ore between the shelves. The openings P in these walls are made smallest nearest to the furnace and gradually increase in diameter toward the top. This portion of the apparatus may be divided by one or more arches Q into`as many chambers as may be desired. I show but one arch Q, and this is placed across the vertical end channel between the wall O and the outer wall at that end, so that the heat from the fireplace I will be caused to pass through the lower passages into the vertical chamber R, where it expands, and thence returns through the passages above the arch and into the chamber which connects with the discharge-Hue S, which is suiiiciently larger than the other ues or passages to make a strong draft and carry off all the products from the furnace. The products of combustion will thus pass beneath the inclined shelves and above the surface of the ore because of the natural grade which the ore will take in flowing down through the zigzag passages and the position of the inclined shelves, which will leave spaces between the ore and beneath the upper part of these shelves, through which the products of combustioncan pass. Having reached the chamber R at the end ofthe furnace opposite the fireplace I, the products of combustion and 7o vapors produced will naturally return, because of the suction-draft, through the similar passages above the arch to the dischargetlue S. As herein shown, the roof of the furnace is the only subdivision made; but if found desirable or necessary it would be within the scope of my invention to interpose a partition or arch in the chamber R above the lowest return-passage and another in the chamber above the first arch Q, so as to make 8o the products of combustion pass back and forth more than once. The heat in this lower portion of the furnace is sufficient to desulfnrize the ore ifit contains sulfur and to vaporize the quicksilver, so that it will pass off,

and by reason of the ore having been thoroughly dried and the moisture therefrom carried off through the discharge-flue L there will be no moisture to escape with the quicksilver-fumes through the passage S from the 9o roasting portion of the furnace.l This will prevent in a great measure the formation of moist acid products, which would otherwise soon destroy the condensers, and it also prevents the formation of what is known as mercuric soot,7 which must afterward he retorted at an additional expense.

The feed from the upper drying to the lower roasting portion of the furnace is direct and continuous, and the rapidity of the feed de- ICO pends upon the drawing off of the ore from the bottom of the furnace.

Above the discharge-passages H are cnlarged cooling-chambers T, into which the ore, descends from the lowermost of the shelves, and these chambers being situated below the horizontal plane of the grate are not subjected to heat therefrom. The ore is thus allowed to partially cool and any remaining mercury will pass olf from it before it reaches the discharge.

I have shown gates U, which are provided with rack-bars V upon the back, and these are engaged by toothed wheels W', mounted upon journaled shafts, with suitable means for turn- 1 15 ing them, so that the gates may be opened or' closed, sliding in vertical guides. By these gates the flow of the ore is regulated, and the angle of the inclined shelves and the discharge-passages is such that when the ore is 12o allowed todo so it will flow freely by gravitation, the only check being in the gates or the banking up of the ore at the foot of the discharge.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a quicksilver-furnaee, inner and outer walls the former having passages or openings through them, roasting and drying chambers 13o ber and located between the inner and outer walls, with the fireplace and discharge-flue of one chamber separate and independent of the fireplace and flue of the other chamber, and means for supplying ore at the top of one chamber and discharging it at the bottom of the other chamber.

3. In a Quicksilver-furnace, the outer walls thereof and superposed roasting and drying chambers having reversed inclined shelves over which the ore passes by gravitation, intermediate passages through which the ore is delivered from the drying-chamber into the roasting-chamber, independent escape-fines through which the moisture is discharged from the drying -chamber and the vapors from the roasting-chamber, a fireplace built at one end of the drying-chamber, passages through the opposite walls of the chamber and a Wall intermediate between the fireplace and the adjacent wall of the drying-chamber, said intermediate wall having passages therefrom corresponding with those in the walls of the drying-chamber.

4.-. In a Quicksilver-furnace, the outer walls thereof and superposed roasting and drying chambers having oppositely-inclined shelves over which the ore passes by gravitation and forming channels from end to end beneath the shelves and openings made in the endwise Walls of the chamber, said openings beL ing made of a gradually-increasing diameter from the furnace upward to the discharge.

5. In a quicksilver-furnace, the outer walls thereof and superposed roasting and drying chambers with intermediate connecting-passages, oppositely-inclined alternating shelves over which the ore passes by gravitation, a fireplace and passages connecting it with the drying-chamber, an escape-liuc through which products from the drying-chamber escape, a second fireplace communicating with the roasting-chamber, passages through the walls thereof and means whereby the heat products are caused to pass backward and forwardly through the roasting-chamber and escapeflue, into which said products are delivered, said iue being separate and independent from the escape-fine of the drying-chamber.

6. In a quicksilver-furnace, the outer Walls thereof and superposed roasting and drying chambers with intermediate connecting-passages, separate replaces one communicating with the roasting-chamber and the other communicating with the drying-chamber, discharge-nues independent of each other and one in communication with each chamber, through which the products of combustion may pass, enlarged cooling-chambers below the furnace-level of the roasting-chamber and inclined discharge-passages through which the ore may flow by gravitation, and control ling-gates by which the discharge from said passage is regulated.

In Witness whereof I have hereunto set my hand.

HUGH C. DAVEY. Witnesses:

S. H. NoURsE, J nssln C. BRoDrE. 

